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Coming dissertations at MedFak

  • Deciphering Binding Patterns of Therapeutic Antibodies with Immune Cells : From Method Development to Application Author: Sina Bondza Link: Publication date: 2020-04-15 13:56

    Reversible binding, for example between signaling molecules and receptors on the cell surface, is one of the main means to communicate information in cellular systems. Knowledge about how molecules interact is crucial for both understanding biological function and for therapeutic intervention. The cellular environment often makes ligand-receptor interactions complex with the membrane providing structural support and containing other components that interfere with the interaction. One of the fastest growing drug classes for targeting cellular receptors are monoclonal antibodies (mAb), in particular within oncology. Therapeutic mAbs can have direct effects on target cells mediated via the Fab-domain and immune-related effects that are mediated via the Fc-domain. An example of the latter is activation of the complement system by binding of its first component C1q to Fc-domains. Furthermore, immune cells can recognize Fc-domains via Fc-receptors and cause target cell death by a process called antibody-dependent cellular cytotoxicity (ADCC).

    Increased understanding about structure-binding-function relationships facilitates rational drug design, as has been demonstrated with the development of next-generation mAbs that harbor a structural modification on their Fc-domain that strengthens the interaction with immune cells thereby increasing ADCC efficacy. In this thesis, assays for characterizing mAb binding and mAb mediated interactions on live cells were developed and applied to illustrate how detailed knowledge about binding processes helps to understand the relation between binding and biological function.

    Paper I describes a protocol for real-time interaction analysis of antibodies with live immune cells enabling binding measurements in a relevant cellular context with the data resolution needed to study complex binding processes.

    Paper II presents a novel real-time proximity assay that allows to study binding kinetics in connection with receptor dimerization and clustering thereby aiding in decipher complex interactions.

    In paper III, binding patterns of the CD20 mAbs rituximab, ofatumumab and obinituzumab were established on cells revealing that the fraction of bivalently bound mAbs differed resulting in dose-dependent affinities for rituximab and obinituzumab.

    In paper IV, a C1q binding assay to mAb opsonized cells was developed and it was shown that a higher degree of bivalent binding correlated with stronger C1q binding for the CD20 mAbs evaluated in paper III.

    In paper V, an assay to study mAb mediated cell-cell interactions was set-up and it was found that neutrophil engagement with target cells was similar for antibodies of IgG and IgA isotype.

  • Patient-reported and medical outcomes in patients treated for diabetic macular edema : A real-world longitudinal study Author: Therese Granström Link: Publication date: 2020-04-03 11:22

    Background Diabetes mellitus can lead to complications, when the complication affects the eyes it is called retinopathy. This can affect the macula and lead to severe loss of vision, diabetic macular edema (DME). This condition has traditionally been treated with laser. However, in 2011, anti-vascular endothelial growth factor (anti-VEGF) injections in the eye were approved as a treatment for diabetic macular edema, and started to be used in eye clinics.

    Aim The overall aim of this thesis was to describe patient-reported outcomes and medical outcomes (PRO) in people treated for diabetic macular edema in a real-world setting in a long-time follow-up study in Sweden.

    Methods Participants were enrolled at two eye clinics at two county hospitals in Sweden between 2012 and 2014. Patient-reported outcomes were measured using a vision-specific questionnaire, the 25-question National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and a generic questionnaire, the Short Form-36 Health Survey (SF-36). Completed questionnaires, medical data such as visual acuity (EDRS), macula swelling (OCT) and social background characteristics were collected before treatment start, at one-year and four-year follow up points. The data was analyzed, descriptive statistics developed and comparative analyses were performed. Interviews were performed before treatment start and were analyzed using qualitative content analysis.

    Results A total of 59 participants were included at baseline. The mean age was 69 years, with an equal gender distribution. At baseline, the participants scored a low general health with the vision-specific questionnaire. In total, 21 participants were interviewed, and a theme emerged of ‘being at a crossroads and a crucial phase in life with an uncertain outcome’. The participants expressed thoughts and concerns at different levels, including practical concerns about the treatment procedure and more existential thoughts about hope for improved visual acuity or fear of deterioration. The results at the one-year follow up showed that 30 patients had improved visual acuity and reported an improvement in several subscales in the NEI VFQ-25. The remaining 27 participants had no improvement in visual acuity or in the vision specific questionnaire. The four-year follow-up involved 37 people, and the result showed significant improvement in subjective near-vision activities and improved distance visual acuity.

    Conclusion: Before treatment, the participants reported low general health and expressed concerns about the injection treatment and their vision. One year after treatment started, the results showed significant improvement in several NEI VFQ-25 subscales, decreased macula swelling and improved visual acuity. These positive results remained at the four-year follow-up point.

  • Inflammation in asthma: relation to symptomatology, exacerbations and lung function Author: Ida Mogensen Link: Publication date: 2020-04-01 14:29

    Asthma is an inflammatory disease in the airways. It is characterized by respiratory symptoms such as wheezing, variable airflow obstruction and impaired lung function development. A better understanding of the underlying inflammation is crucial in order to treat and prevent asthma symptoms and lung function deterioration.

    We have evaluated six inflammatory markers in relation to asthma symptoms, asthma attacks, and lung function measures (fixed airflow obstruction (FAO) and lung function development over time) in five investigations. The markers (elevated levels) were fraction of exhaled NO (FeNO) (elevated ≥25ppb), serum eosinophil cationic protein (S-ECP) (≥20 µg/L), blood eosinophils (B-Eos) (≥300 cells/µL), urinary eosinophil derived neurotoxin (U-EDN) (≥65.95mg/mol creatinine), serum periostin (S-periostin) ( ≥74μg/L), and blood neutrophils (B-Neu) (≥5,100 cells/µL).  The studied populations consisted of mainly adults (except in Paper II) and included asthmatics from the Swedish part of the Global Allergy and Asthma European Network survey (Papers I and III), the American National Health and Nutrition Examination Survey (Papers II and IV), the Uppsala part of the European Community Respiratory Health Survey I-III, the Vlagtwedde and Vlaardingen study, and the Rotterdam study, the latter two from the Netherlands (Paper V). All study populations were population based, and the asthmatics included had mainly mild to moderately severe asthma.

    The main findings are that simultaneously elevated FeNO and S-ECP are associated with more reported asthma symptoms and attacks, and elevated FeNO and B-Eos are associated with lower lung function, suggesting a value in measuring both local (FeNO) and systemic (S-ECP, B-Eos) inflammation in asthma. Eosinophil inflammation (elevated U-EDN and S-ECP) was associated with FAO in asthma, while the other type-2 markers FeNO and S-periostin were not. Elevated B-Eos was further associated to lower lung function measures in a general population, and a faster lung function decline in asthmatics. FeNO was more often elevated in asthmatics, but was difficult to robustly associate to a specific disease characteristic. B-Neu was associated to FAO in participants with current smoking or pronounced smoking history.

    In conclusion, asthma with elevated markers for eosinophil inflammation was associated to worse morbidity and lung function development in comparison with asthmatics without elevated markers for eosinophil inflammation. These results indicate ongoing eosinophil inflammation in asthma as closely associated to disease activity and the absence of eosinophil inflammation to less morbidity.